1. Field of the Invention
The present invention relates to a non-volatile memory system and a method for reading data therefrom. More particularly, the present invention relates to a non-volatile memory system that allows data to be read quickly and a method for reading data therefrom.
2. Descriptions of the Related Art
The rapid pace of modern technology development has led to the proliferation of various information contents. Accordingly, a wide variety of storage media have emerged to facilitate data storage to record and store such information. Particularly, non-volatile memories, which can retain data without a power supply and allows data to be read and written repeatedly, have found a widespread use in many electronic products. Among these non-volatile memories, flash memories are gradually replacing other non-volatile memories such as magnetic disks or compact disks due to the flash memories' small profile, good portability, and convenience.
Generally, to read data from one of the storage units of a flash memory, the following sequence of steps are executed: a controller sending a command to a storage unit; the storage unit receiving an address of a sub-data of the data; all the sub-data being read from a storage array of the storage unit to a register of the storage unit according to the command and the address of the sub-data; and finally, the controller reading the sub-data from the register. Since the data typically comprises a plurality of sub-data, this sequence is then repeated until all the sub-data (i.e. the complete data) have been read.
With the rapid development of flash memories, each storage unit can now store increasingly more information, resulting in an increase of time needed to read data from the storage array to the register (tR). On the other hand, to reduce the time of reading data from the storage unit, there is less time spent on reading data from the register. However, due to various limitations, the extent to which the tR and tRC can be reduced is limited, therefore, it is important to develop a technology that can effectively reduce the time of data reading.
Presently, a number of technologies have been proposed in an effort to reduce the time needed to read data. For example, an apparatus for reading data from several flash memories and a method thereof have been disclosed in U.S. Pat. No. 6,131,139. According to the disclosure thereof, all the flash memories are first enabled, and then a read command and an address of data to be read are transmitted to the flash memories. Subsequently, a respective storage array in the flash memories stores the data temporarily into a respective register before the data is read from the individual memories. With this method, the temporary storage of data can be accomplished simultaneously for the individual flash memories, thereby, reducing the time needed to read data from the storage array to the register (tR). However, after completing the data reading from the individual flash memories, the next data reading operation still temporarily stores the data simultaneously, which means that the saved time is limited.
In summary, there are not many methods currently for reducing the time needed to read the data. Therefore, efforts still have to be made in the art to provide a mechanism that can effectively reduce the time of reading data from the memory, thereby, improving the overall performance of the memory.